3x+6---- =2a

3x+6=2a

subtracting 6 from both sides

3x+6-6 =2a-6

thus 3x = 2a-6

dividing both sides by 3

3x/3=(2a-6)/3

hence x=(2/3)a-6/3

x=(2/3)a- 2

3x = 2a - 6

x = (2a - 6) / 3

x = 2a/e - 2